[X-Unix] Re-attaching to an X Session?

[Paul]

Hi.

I know of the GNU screen utility but have never used it: usually  
nohup is good enough for me.

But when it comes to X11 apps, is there any way of re-attaching to a  
remote ssh -Y session, and not having the processes die when you  
close the lid of the local iBook?

Thanks.

Paul